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Advances in OptoElectronics
Volume 2007 (2007), Article ID 69578, 11 pages
http://dx.doi.org/10.1155/2007/69578
Research Article

Silicon Quantum Dots in a Dielectric Matrix for All-Silicon Tandem Solar Cells

1ARC Photovoltaics Centre of Excellence, University of New South Wales, Sydney 2052, NSW, Australia
2ARC Centre of Excellence for Coherent X-Ray Science, Swinburne University of Technology, Hawthorn 3122, VIC, Australia

Received 1 April 2007; Accepted 26 June 2007

Academic Editor: Armin G. Aberle

Copyright © 2007 Eun-Chel Cho et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We report work progress on the growth of Si quantum dots in different matrices for future photovoltaic applications. The work reported here seeks to engineer a wide-bandgap silicon-based thin-film material by using quantum confinement in silicon quantum dots and to utilize this in complete thin-film silicon-based tandem cell, without the constraints of lattice matching, but which nonetheless gives an enhanced efficiency through the increased spectral collection efficiency. Coherent-sized quantum dots, dispersed in a matrix of silicon carbide, nitride, or oxide, were fabricated by precipitation of Si-rich material deposited by reactive sputtering or PECVD. Bandgap opening of Si QDs in nitride is more blue-shifted than that of Si QD in oxide, while clear evidence of quantum confinement in Si quantum dots in carbide was hard to obtain, probably due to many surface and defect states. The PL decay shows that the lifetimes vary from 10 to 70 microseconds for diameter of 3.4 nm dot with increasing detection wavelength.